//283. 移动零
import java.util.*;
class Solution {
    public void moveZeroes(int[] nums) {
        ArrayList<Integer> list = new ArrayList<>();
        int n = nums.length;
        for(int x : nums){
            if(x!=0){
                list.add(x);
            }
        }
        int k = 0;
        for(int i = 0;i<n;i++){
            if(i<list.size()){
                nums[k++]=list.get(i);
            }else{
                nums[k++]=0;
            }
        }
    }
}


//15. 三数之和(双指针)
class Solution1 {
    public List<List<Integer>> threeSum(int[] nums) {
        List<List<Integer>> result = new ArrayList<>();
        int n = nums.length;
        Arrays.sort(nums); // 先排序

        for (int i = 0; i < n - 2; i++) {
            if (i > 0 && nums[i] == nums[i - 1]) {
                continue; // 跳过重复的元素
            }

            int left = i + 1;
            int right = n - 1;
            while (left < right) {
                int sum = nums[i] + nums[left] + nums[right];
                if (sum == 0) {
                    result.add(Arrays.asList(nums[i], nums[left], nums[right]));
                    // 跳过重复的元素
                    while (left < right && nums[left] == nums[left + 1]) left++;
                    while (left < right && nums[right] == nums[right - 1]) right--;
                    left++;
                    right--;
                } else if (sum < 0) {
                    left++;
                } else {
                    right--;
                }
            }
        }
        return result;
    }
}